Move comment to license_note

Comments no preserved during refresh.

Test: m nothing
Change-Id: I1af3342e7c603cf520c4c867df0e0807f6ec4544
diff --git a/METADATA b/METADATA
index 1cee8f8..0306d85 100644
--- a/METADATA
+++ b/METADATA
@@ -10,7 +10,7 @@
     value: "https://github.com/aquynh/capstone"
   }
   version: "8984920722733400e93f695a0c37a80158341103"
-  # would be NOTICE save for arch/X86/qsort.h
+  license_note: "would be NOTICE save for arch/X86/qsort.h"
   license_type: RECIPROCAL
   last_upgrade_date {
     year: 2020